Jake Wildwood (Banzaigoat)

Slightly different from the other sellers I've listed here as Jake deals only with second hand ukuleles. Jake is an incredibly talented restorer of instruments (not just ukuleles) and often sells ukuleles he has restored on eBay. He has the best listings I've ever seen on eBay with full details of the instrument, photos from every angle and video/sound clips. You can check out his handywork on his blog Antebellum Instruments which often includes many weird and wonderful instruments.

On eBay

On Video